iiS- '-Memlr en the Foj/il CJciit-CBbiic/ 



from Guiana and Peru. Tliis opinion was foon confirmed by 

 chemical analylis: and ibis lingular foflil was the more fought 

 after, and coulidered as a curious object of natural hiRory, as 

 it was more rare; and as it was thought an aftonilliing cir- 

 cumflance, that a fubftance which diilils from exotic trees 

 which grow only in the torrid zone fhould be found between 

 ftrata of argilhucous fchilt in the bofom of the mountains in 

 the northern part of England. 



Lamethcrie mentioned this difcovcry in the Journctl de 

 Vhyjique, \\ ithout giving any details refpefling the place 

 where it was found : he only infiftcd on the analogy be- 

 tween this foUil bitumen and the caout-chouc. 



At that period fome varied fragments of this fubftance 

 were fent to me, together with the matrices in which they 

 had been found ; and as i was acquainted with the places 

 and the ir.ountain where the difcovcry had been made, I 

 mentioned this important faft every year in my geological 

 leAures at the Mufa^um, when I treated of the exotic wood 

 and plants found in a tbflil ftate in countries abfolutcly oppo- 

 lite to ihoie where thefe plants and trees grow at prefent: but 

 I publilhed notlving on the fubje6l:, as has been Obfervcd by 

 Mr. Mawe, proprietor of the princi|)ai mines of fparry fiuor 

 of the neighbourhood of Caftletun, and autlior of The M'me- 

 ralogj! of Derhrjhire, lately publilhed ; a work which will 

 .be exceedingly uVeful to naturalitis who intend lo vifit that 

 county, fo abundant in a variety of mineral produtuions *. 



Mr. Mawe, when laft at Paris, brought nie fome very re- 

 miarkable fpecimens which were wanting in my coUeClion oi 

 ibHil caout-chouc ; and it is mv duty to acknowledge here my 

 gratitude to him. He was fo kind as to give me alfo fome 

 information on this fubject ; and he IhoweJ me. at the fame 

 time a piece of foUil caout-chouc, difcovered not long ago, 

 confilting of an oblong mafs two feet and a half in circum- 

 ference and two inches and a half in thicknefs, weighing 

 about three pounds. It is foft, exceedingly t:ompreiTibIe, 

 and of a black and fomewhat olive colour; folid, hard, and 

 ihining fragments ot a bitumen nearly fimilar are enveloped 

 by, and adhere as it were to. the elallic mafs, both in the 

 infide and on the exterior faces. They are not larger than a 

 • common almond; fome of them are black like jet, other.- of 

 va broivn liver colour. Thcv mav be eaiily detached from 

 the coniprefliblc caout-chouc where thefe hard fragments arc 

 not abundant. 



■ • The Mineralogy of Deibyfhire, with a nelcHption of the mtift imer- 

 tOing Mines in the Noithoif Kiigland, in bcotlaml and Walts. By Jolia 

 AIawc. London 1002. ?vo. one volume, v;ith plates. 



Mr. 



